通过pid获取进程名和通过进程名获取pid

#include <sys/types.h>
#include <dirent.h>
#include <stdio.h>
#include <string.h>
#define BUF_SIZE 1024
void getPidByName(char* task_name)
{
DIR *dir;
struct dirent *ptr;
FILE *fp;
char filepath[50];//大小随意，能装下cmdline文件的路径即可
char cur_task_name[50];//大小随意，能装下要识别的命令行文本即可
char buf[BUF_SIZE];
dir = opendir("/proc"); //打开路径
if (NULL != dir)
{
while ((ptr = readdir(dir)) != NULL) //循环读取路径下的每一个文件/文件夹
{
//如果读取到的是"."或者".."则跳过，读取到的不是文件夹名字也跳过
if ((strcmp(ptr->d_name, ".") == 0) || (strcmp(ptr->d_name, "..") == 0))
continue;
if (DT_DIR != ptr->d_type)
continue;

sprintf(filepath, "/proc/%s/status", ptr->d_name);//生成要读取的文件的路径
fp = fopen(filepath, "r");//打开文件
if (NULL != fp)
{
if( fgets(buf, BUF_SIZE-1, fp)== NULL ){
fclose(fp);
continue;
}
sscanf(buf, "%*s %s", cur_task_name);

//如果文件内容满足要求则打印路径的名字（即进程的PID）
if (!strcmp(task_name, cur_task_name))
printf("PID:  %s\n", ptr->d_name);
fclose(fp);
}

}
closedir(dir);//关闭路径
}
}
void getNameByPid(pid_t pid, char *task_name) {
char proc_pid_path[BUF_SIZE];
char buf[BUF_SIZE];
sprintf(proc_pid_path, "/proc/%d/status", pid);
FILE* fp = fopen(proc_pid_path, "r");
if(NULL != fp){
if( fgets(buf, BUF_SIZE-1, fp)== NULL ){
fclose(fp);
}
fclose(fp);
sscanf(buf, "%*s %s", task_name);
}
}
void main(int argc, char** argv)
{
char task_name[50];
pid_t pid = getpid();
printf("pid of this process:%d\n", pid);
getNameByPid(pid, task_name);

/*
strcpy(task_name, argv[0]+2);
printf("task name is %s\n", task_name);
getPidByName(task_name);
*/
printf("task name is %s\n", task_name);
getPidByName(task_name);
sleep(15);
}